A new empirical mass flow correlation and mass flow rate characteristics of R600a through novel rotary-baffle curved-channel electronic expansion valve

Abstract

The novel rotary-baffle curved-channel electronic expansion valve (RBCC-EEV) has appeared in industry to replace a capillary tube as the variable expansion device in household refrigerators. However, due to the structure differences between the RBCC-EEV and the traditional orifice-type EEV, the previous empirical mass flow correlation inapplicable. In this paper, a new empirical correlation is proposed based on the structure and regulation principle of the novel RBCC-EEV, and the effects of different operating conditions on the mass flow rate of R600a flowing through two different RBCC-EEVs are experimentally investigated. The new empirical correlation introduces a centrifugal force coefficient and a variable length coefficient to represent the effect of asymmetric cavitation phenomenon and super-linear mass flow rate characteristics. The experimental results show a rise in the mass flow rate with increasing inlet pressure, inlet subcooling and opening ratio. Under the test range, the flow pattern of R600a flowing through the RBCC-EEV is chocked flow. Moreover, the proposed new empirical mass flow correlation agrees well with the experimental data. For 95.7 % of the prediction value, the relative deviation is below 15 %, while 89.0 % exhibit a relative deviation less than 10 %. The average deviation and standard deviation stand at 6.52 % and 4.56 %, respectively.